Yes, that is what I found out. Most implementations seem to use the lower
level interface. Is GTK_TREE_MODEL_ROW the only string that is
interpreted as special? Or does any of the frequently used ones, like
'STRING' 'TEXT', 'INTEGER', 'text/plain', also have side-effects?

GTK_TREE_MODEL_ROW is the only target string that gets "special
treatment" inside the tree view, the others should not have
side-effects.
regards,
-kris.